Polymorphic4.T
val name : 'a t -> 'b t -> 'c t -> 'd t -> string
val structural_descr : Structural_descr.t -> Structural_descr.t -> Structural_descr.t -> Structural_descr.t -> Structural_descr.t
type ('a, 'b, 'c, 'd) t
val reprs : 'a -> 'b -> 'c -> 'd -> ('a, 'b, 'c, 'd) t list